Oxidative stress may contribute to the pathogenesis of congenital heart defects, but the role of dynamic thiol/disulphide homeostasis has not been evaluated. The objective of this study was to assess whether there are changes in thiol/disulphide homeostasis and nitric oxide levels in children with tetralogy of Fallot (TOF) and ventricular septal defect (VSD). A total of 47 children with congenital heart defects (24 TOF and 23 VSD) and 47 healthy age- and sex-matched controls were included in this study. Serum total thiol and native thiol levels were measured using a novel automatic spectrophotometric method. The amount of dynamic disulphide bonds and related ratios were calculated from these values. Serum nitric oxide levels were detected using a chemiluminescence assay. We found that the average native thiol, total thiol, and disulphide levels were decreased in patients with VSD when compared with healthy individuals (p < 0.001, p < 0.001, and p < 0.01, respectively). While native thiol levels were decreased (p < 0.01), disulphide levels were elevated in the TOF group (p < 0.05). We observed marked augmentation of disulphide/native thiol (p < 0.001) and disulphide/total thiol ratios (p < 0.01) in the TOF group. However, there was a significant decrease in native thiol/total thiol ratio in patients with TOF. No significant changes in these ratios were noted in the VSD group. We detected significant elevations in serum nitric oxide levels in children with TOF and VSD (p < 0.001 for all). These results are the first to demonstrate that thiol/disulphide homeostasis and nitric oxide are associated with TOF and VSD in children.

Background Alteration in thiol level under oxidative stress may contribute to community‐acquired pneumonia (CAP). The goal of this study was to determine whether there are changes in thiol/disulfide homeostasis and nitric oxide (NO) in children with CAP. Methods In total, 130 participants were involved in the study. Of these, 65 had been diagnosed with CAP on admission, and the remaining 65 were healthy individuals. Serum total thiol and native thiol were measured in each participant using a novel automated spectrophotometric method. The amount of dynamic disulfide bonds and related ratios were calculated from these values. Serum NO was measured on chemiluminescence assay. Results Average native thiol, total thiol, and disulfide in the CAP group were significantly lower than in the healthy individuals (P < 0.0001, P < 0.0001, P = 0.0126, respectively). In addition, disulfide/native thiol (P = 0.0002), and disulfide/total thiol ratios (P = 0.0004) were significantly higher, whereas the native thiol/total thiol ratio (P = 0.0004) was lower in the CAP group. High serum NO was noted in the CAP group (P = 0.0003), but there was no marked correlation between thiol/disulfide and NO. Conclusion The changes in endogenous thiol levels under oxidative stress may be associated with the pathogenesis of CAP in pediatric patients.

Oxidative stress may play a role in the pathogenesis of immune thrombocytopenia (ITP), but the role of dynamic thiol/disulfide homeostasis has not been studied. The objective of this study was to assess whether there is a change in thiol/disulfide homeostasis in children with acute ITP. A total of 40 children with acute ITP and 50 healthy age-matched and sex-matched controls were included in this study. Serum total thiol and native thiol levels have been measured with a novel automatic spectrophotometric method. The amount of dynamic disulfide bonds and related ratios were calculated from these values. The average total thiol and native thiol levels of the patient group were found to be significantly lower than those levels of controls (P<0.01). However, intravenous immunoglobulin (IVIG) treatment with 1 g/kg/d prevented these reductions. disulfide level was slightly, but not significantly, depressed in ITP patients, but it recovered following IVIG treatment. We detected no marked changes in disulfide/total thiol, disulfide/native thiol, and native thiol/total thiol ratios between groups. These results are the first to demonstrate that thiol/disulfide homeostasis plays a role in ITP pathogenesis, and IVIG treatment can prevent the reduced thiol levels in children.

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Recognizing variability of coronary artery anomalies is critical when considering surgical or interventional therapies in children with congenital heart disease.